In the second sentence "Elle est triste parce qu'elle a une larme sur la joue.", the Sebastien character pronounces the article "une" ooneh instead of oon. It sounds like he's saying une alarme. I've listened to that passage multiple times and I can hear it clear as a bell.
In the seventh sentence "Oui, elle a besoin d'une sieste !", the other character pronounces the article "une" as oon. There is a distinct difference between the two characters' pronunciations.
Is this a difference in dialects that one just has to adapt to and if so where is it most likely to be encountered? I could see this causing confusion.